Coating process.



J.P.A.McCOY.

COATING PROCESS,

APPLICATION FILED JULY 3,1914.

1 ,268,030. Patented May 28,1918.

WHNESSES: INVENTOR IV 1 ,WV Z Ia/mg P/f I'M/:50)

WWW W/ ATTORNEY UNITED STATES PATENT OFFICE.

JAMES P. A. MCCOY, OF \KTILKINSBURG, PENNSYLVANIA, ASSIGNOR TOWESTINGHOUSE ELECTRIC AND MANUFACTUBIN G COMPANY, A CORPORATION OFPENNSYLVANIA.

COATING PROCESS.

Specification of Letters Patent.

Patented May 28, 1918.

Application filed July 3, 1914. Serial No. 848,804.

To all whom it may concern:

Be it known that I, JAMFs P. A. MoCoY, a subject of the King of GreatBritain, and a resident of Wilkinsburg, in the county of Allegheny andState of Pennsylvania, have invented a new and useful Improvement inCoatin Processes, of which the following is a specification.

My invention relates to processes of covering solid bodies with metallicor non-metallic coatings, and it has for its object to provide a coatingrocess in which the coating material is de ivered upon the surface ofthe article to be coated in the form of a fine spray of molten material,the particles composing the spray being so small that the materialsolidifies instantl upon reaching the surface of the article toliecoated.

In the accompanying drawing, Figure 1 is a diagrammatic viewillustrating one form of apparatus suitable for carrying out my process,and Fig. 2 is a longitudinal sectional view of a combined torch nozzleand delivery device adapted for use in another form of apparatus.

My invention may be considered as an extension of, and an improvementupon, the well-known Schoop metallizing process, according to onemodification of which a bath of molten metal is disintegrated by a rapidcurrent of compressed and heated gas, the resulting spray bein deliveredby the current of gas to the col d surface of the article to be coated.According to another modification of the Schoop process, a wire of themetal to be used as the coating is fed into the flame of an oxyhydrogenor oxyacetylene torch, which melts the end of the wire and projects theresulting spray of molten metal against the article to be coated, as inthe first modification of the process.

According to my improved process, I am not restricted to the use ofmetal as the coating material, but I nay coat solid objects with eithermetallic or non-metallic substances. If the coating is to be metallic, Iproceed by feeding an oxid of the coating metal, in finely divided form,and at a definite rate, depending upon the nature of the oxid and thethickness of the desired coating,

into the flame of an oxyhydrogen or oxyacetylene torch which is directedtoward the body to be coated. The oxids are reduced to a liquid metalliccondition in the reducing flame of the torch, and are blown against theobject to be coated as in the Schoop process. Other readily-reduciblemetallic compounds may be substituted for the oxids.

If a non-metallic material, such as silica or alumina, is to be used asthe coating material, it is fed into the flame of the torch in a finelydivided condition, as in the case of the metallic oxids. Here, however,there is no chemical transformation of the coating substance, but it ismerely melted, and the spray of molten material is directed against theobject to be coated as in the other methods described.

In order to intensify the heat, and provide a larger melting andreducing area into which the coating powder is introduced, a torchhaving several united streams of oxygen and acetylene, hydrogen, orother combustible gas may be employed.

Even the most fragile and combustible materials, such as cloth, paperand lace, may be coated with molten material by my process, since theindividual particles which compose the molten spray are cooled andsolidified so rapidly, upon reaching the article that is being coated,that the article is not burned or otherwise injuriously affected.

One valuable application of my invention is the coating of metallicresistance elements and other electric apparatus with insulatingcoatings of silica, alumina, or other highly refractory insulatingmaterial. In this case, and in any other case where a metallic body,that is subsequently to be heated, is coated with silica or othernon-metallic brittle substance, the metal should be heated before beingcoated in the manner described above. This is necessary because, if themetal is coated when cold and afterward heated, its expansion will breakthe brittle refractory coating.

The finely divided coating material may be fed into the flame of thetorch in any convenient manner. As shown in Fig. 1 of the accompanyingdrawing, the powdered material is placed in a hopper 1, thatcommunicates with a worm conveyer-2, the delivery end 3 of which isdisposed directly above the flame 41 of an oxyacetylene, oxyhydrogen orother form of torch 5 that is directed toward the object 6 to be coated.As shown in the drawing, the object 6 is a continuous web or filament offlexible material that is unwound from a roll 7 and passes across thepath of the flame 4 and around a guide roller 8, the coated web beingrewound on a roller 9.

Instead of dropping the powdered coating material transversely into theflame, as in the apparatus shown in Fig. 1, the material may be fedthrough a passage that is centrally disposed within the nozzle of thetorch. A nozzle provided with such a passage for feeding the coatingmaterial, is illustrated in Fig. 2, wherein a nozzle 10 is shownprovided with a plurality of annular ports 11 and 12 through whichoxygen and hydrogen acetylene, or other combustible gas, may e fed intothe combustion chamber 13 at the outer extremity of the torch. A centralpassage 14: is disposed within and inclosed by the walls of the ports 1]and 12. It will be evident that powdered material, fed through thepassage 14 in any convenient manner, will be received in the highlyheated combustion chamber 13, and, if the coatin material is a metallicoxid, it will be reduce to metal therein. A torch having several nozzles10 may be employed, the nozzles being so disposed that their flames areunited, thus forming a large heating and reducing field. When such anarrangement is adopted, only a single material-feeding passage 14 isrequired, and this passage is preferably disposed symmetrically withrespect to the nozzles of the torch. Thus, one of the series of nozzlesmay be constructed, as shown in v Fig. 2, with the passage 14: therein,and the remaining nozzles of the torch may be constructed without thepassage 14:.

It is to be understood that the apparatus shown is merely illustrative,and that any other convenient means may be employed for feeding adefinite amount of the powdered coating material into the flame 'of thetorch. It will also be obvious that the object to be coated is notnecessarily presented to the spray of metal in the form of a continuousweb or filament, since any desired solid article may be coated accordingto my process.

Any metallic oxids that are capable of being reduced to metal in a flameof high temperature may be employed in my process,

and all non-metallic substances are likewise suitable for my use thatcan be melted without combustion in such a flame. My process may,therefore, be carried out with a wide variety of non-metallic substancesand with nearly all metallic oxids. In view of the wide range ofconditions under which my on my invention except such as are indicatedin the appended claims.

I claim as my invention:

1. A coating process that comprises reducing and liquefying a powderedmaterial consisting of a metallic compound and projecting the liquidagainst the surface to be coated.

2. A coating process that comprises reducing and liquefying a powderedmaterial consisting of a metallic oxid and projecting the liquid againstthe surface to be coated.

3. A coating process that comprises reducing a powdered materialconsisting of a metallic compound to molten metal and simultaneouslyprojecting the reduced metal against the surface to be coated.

4. A coating process that comprises reducing a powdered materialconsisting of a metallic oxid to molten metal and simultaneouslyprojecting the reduced metal against the surface to be coated.

5. A coating process that comprises reducing a powdered materialconsisting of a metallic compound to molten metal and simultaneouslyprojecting the reduced metal in the form of a spray against the surfaceto be coated.

6. A coating process that comprises reducing a powdered materialconsisting of a metallic oxid to molten metal and simultaneouslyprojecting the reduced metal in the form of ,a spray upon the surface tobe coated.

7. A coating process that comprises reducing a finely-divided metalliccompound to molten metal and simultaneously projecting the reduced metalagainst the surface to be coated.

8. A coating process that comprises re ducing a finely-divided metallicoxid to molten metal and simultaneously projecting the reduced metalagainst the surface to be coated.

9. A coating process that comprises introducing a powdered materialconsisting of a metallic compound into a flame that is directed towardthe surface to be coated, whereby the said compound is reduced to metaland projected in a spray against the said surface.

10. A coating process that comprises introducing a powdered materialconsisting of a metallic oxid into a flame that is directed toward thesurface to be coated, whereby the said oXid is reduced to metal andsimultaneously projected in a spray upon the said object.

11. A coating process that comprises introducing a finely-dividedmetallic compound into a reducing flame thatis directed is reduced tomolten metal which is pro- 10 toward the surface to be coated, wherebythe jected in a spray upon the said surface. said compound is reduced tomolten metal In testimony whereof I have hereunto subwhifch is projectedin a spray upon the said scribed my name this 30th day of June, 1914.

5 en ace.

12.- A coating process that comprises in- JAMES MCCOY troducing afinely-divided metallic oxid into Witnesses: a. reducing flame that isdirected toward the W. H. KEMI'DON, surface to be coated, whereby thesaid oxid B. B. Hnms,

